Means for defibrating and grinding paper pulp or other fibrous material



Dec. 1, 1953 c. LAVISTE 2,660,934

MEANS FOR DEFIBRATING AND GRINDING PAPER PULP OR, OTHER FIBROUS MATERIAL Filed July 16, 1948 3 Sheets-Sheet l 1953 c. LAVISTE MEANS FOR DEFIBRATING AND GRINDING PAPER PULP OR OTHER FIBROUS MATERIAL 3 Sheets-Sheet 2 Filed July 16, 1948 Dec. 1, 1953 VlSTE 2,660,934

C. LA MEANS FOR DEFIBRATING AND GRINDING PAPER PULP OR OTHER FIBROUS MATERIAL Filed July 16, 1948 3 Sheets-Sheet 3 Patented Dec. 1, 1953 MEANS FOR DEFIBR-ATING AND GRINDING PAPER PULP OR OTHER FIBROUS MATE- RIAL Cornelius Laviste, Skonsberg, Sweden- Application July 1c, 1948, Serial No. 39,133

Claims priority, application Sweden July 18, 1947 'Il'iepresentinvention relates to means for defibrating and grinding paper pulp or. other fibrous material and comprises a rotatable roller arranged in a container, the said roller being provided with defibrating. and grindingmemberscooperating with a number of knives not participating in the rotation, the edge portions of the knives serving as defibrating and grinding members and facing the roller. The substantial feature of the invention is that the broadsides of the knives form walls in a number of narrow throughepassages which are completel open towards. the roller to allow the treated pulp to pass freely from the defibrating and grinding zone to a chamber located outside the said zone and communicating with an outlet. At the rotation of the roller the treated pulp is compelied, under'the action of the centrifugal force, to pass through the passages between the knives to the chamber located outside the said knives and from there to the said outlet.

According to the invention it is possible to use very high pulp concentrations and to obtain a very good defibrating and grinding effect. Other advantages Will appear from the following de scription.

Two embodiments of. the invention are illustrated in the accompanying drawings.

In the drawings:

Fig. 1 is avertical longitudinalsection through the device according to the one" embodiment.

Fig. 2 is a cross section on the line 22, 1.

Fig. 3 is a vertical longitudinal section through the device according to the second embodiment.

Fig. 4 is a cross section on the line 4-4, Fig. 3.

In the embodiment according to Figs, 1 and 2 a preferably conical roller 2 is rotatably mounted in a container I, the shell or. envelope surface 3 of' the said conical roller being non-perforated, i. e. it has no through-openings. The roller 2 which is fixed on a rotatably mounted shaft 5 bymeans of a sleeve 4, is on its surface 3 pro vided with a number of longitudinal knife-shaped defibrating and grinding members suitably spaced over the entire periphery. The sleeve 4' is connected with the shell 30f the roller 2 by means of a number of radial arms I. The shaft 5 has a tight fit in the end Walls of the roller 2' as indicatedat 5a and extends through packing boxes 51) in the end walls of the container I. The knives 6 operate against a number of longitudinal non-rotatable defibrating and grinding members in the form of knives8.

The knives 8 arearranged in such a manner that open throughmassagesflare formed between 3 Claims. (CI'. 92-26) them, the pulp treated by means of the knives 6 and 8 being led off through the said passages to a chamber II) located outside the knives and. communicating with the-outlet II. I The knives 8- are carried and retained in their proper positions'by means of a number'of suitably spaced rings, i. e., connecting members, I2 fixed to the container I.

'As is bestdisclosed in Fig. 2, the knives 8: surround the periphery ofthe roller 2 except at that point where the pulp inlet I 3" provided at the top, is situated. Consequently, the knives8. surround the greatest part of the periphery of the roller 2.

The shaft 5 is adapted to be'actuated bymeans of a known adjusting device I 4 by meansof which the shaft and thus also the roller 2 can be displaced in the longitudinal direction so that the distance between the rotatable knives 6" and the non-rotatable knives 8 cooperating with the knives 6 can be changed for controlling the grinding pressure;

The pulp issupplied through the inlet I3 and will, by virtue of' its'weight, fill the spaces between the knives IS: on the roller 2. At the rotation of the roller, the supplied pulp is subjected to an intensive treatment by the knives 6 coopcrating with the non-rotatable knives 8 so thatan efiective defibration and grinding of the pulp is obtained. Due to the centrifugal force, the pulp introduced into the spaces between the knives 8 will at the rotation of the roller .2 be thrown outwardly towards the non-rotatable knives 8. At the rotation of the roller the treated pulp" is forced by the centrifugal force to pass through thepassagesbetween the knives 8 about radially outwards to the chamber III from where it isconveyed to the outlet I I.

The d'evice'isintended for continuous defibration and'grinding. In special cases, e, g. inca'se of rag pulp, the treatment can also; if desired, take place discontinuously, in which case the pulp which has passed through the device, is ina known manner conveyed-back to the inlet of the device for new treatment.

In the previously known defibrating. and grinding devices of this type the power consumption m unnecessarily high because the greatest part of the energy is used for conveying'the pulp through the grinding aggregate. It is namely a well-known fact that'in ordinary beaters the pulp must pass the non-rotatable knives a great many times before it has become sufficiently ground, the outermost non-rotatable knives only exerting" a real grinding effect. In the device according to the present invention on the other hand, the energy is substantially used for the difibrating and grinding proper, and each of the non-rotatable knives has a grinding effect, as the pulp already ground always has a possibility of passing freely between the non-rotatable knives and of leaving the grinding zone. The power consumption, calculated per ton paper, becomes considerably smaller than according to the known grinding devices, because, as has appeared from the foregoing statements, the pulp leaves the grinding zone immediately as it has been ground, and thus need not unnecessarily be conveyed round the whole grinding device. According to the invention the centrifugal force of the rotating roller is utilized to continuously feed the pulp between the rotating and the nonrotating knives, and to force the ground pulp to pass between the last-mentioned knives and to leave the grinding zone. Thus, as the centrifugal force has an advantageous influence upon the grinding process, the roller may have a much greater speed of rotation than the roller in the previously known grinding devices of this type, and consequently, the grinding capacity is correspondingly increased. According as desired, free or greasy pulp may be produced.

The embodiment according to Figs. 3 and differs from the construction previously described substantially in the provision of two inlets l3, one at each end of the rotatable roller 2, through which inlets the pulp is introduced into the interior of the roller, and in that the said roller is formed of the suitably spaced knives 6, which are not, as in the embodiment according to Figs. 1 and 2, arranged on a nonperforated shell, but are carried and retained in their positions by rotatable connecting members l5, so that passages l6 extending through the knives 6 are formed between the interior of the roller formed by the knives 6 and by the non-rotatable knives 8. The pulp introduced into the interior of the roller can thus pass through the passages It to the non-rotatable knives 8 at the rotation of the roller. In contradistinction to what is the case in the embodiment according to Figs. 1 and 2, the non-rotatable knives 8 according to Figs. 3 and 4 surround the entire periphery of the rotatable roller 2. The knives 8 are carried and retained by connecting members [2 fixed to the container I, just as in the embodiment according to Figs. 1 and 2. The previously mentioned rotatable connecting members 15 are connected with the sleeve 4 by means of arms H, the said sleeve being fixed on the rotatably mounted shaft 5 which, also in this embodiment, is adapted to be actuated by an adjusting device l4. As shown in Fig. 3, some of said arms may be inclined outwardly from the sleeve to the connecting members which disposition of the arms tends to aid in the uniform distribution of pulp along the inner face of the roller. At their lower parts the inlets l3 may be formed to two passages I8 which open into the rotatable roller 2, one on each side of the shaft 5 (Fig. 4).

The device according to the embodimentnow described has the same advantages as the device according to the embodiment shown in Figs. 1 and 2. However, the grinding capacity and effect are still greater than in the last-mentioned embodiment because the non-rotatable knives 8 according to Figs. 3 and 4 surround the entire periphery of the rotatable roller. In the embodiment according to Figs. 3 and 4 the centrifugal force of the rotatable roller is utilized much better than in the embodiment first de-' scribed because the pulp supplied to the interior of the roller 2 in the embodiment according to Figs. 3 and 4 will be thrown outwardly through the passages l6 between the rotatable knives 6 to be ground between the said knives and the non-rotatable knives 8, whereafter the ground pulp leaves the grinding zone by being compelled to pass through the passages 9 between the nonrotatable knives B to the chamber Ill and from there to the outlet H. As the pulp in the embodiment according to Figs. 3 and 4 is supplied through both ends of the rotatable roller 2, it will be spread and distributed along the entire length of the roller in such a quantity that in operation the roller always contains a certain reserve of pulp, which guarantees an even and continuous feeding. The high grinding capacity makes the device very suitable for grinding to produce all qualities of paper. The production capacity of the device according to Figs. 3 and 4. is still greater than that of the device according to Figs. 1 and 2.

Of course, the described and disclosed embodiments may be varied in many respects without departing from the idea forming the basis of the invention.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. Apparatus for defibrating and grinding paper pulp or other fibrous material, comprising a container, an open-ended rotatable roller disposed within the container, said roller having a peripheral working face comprised of a plurality of longitudinally extending, spaced, defibrating and grinding knives arranged close to each other and having end and intermediate connecting members between the knives making the working face of the roller into a rigid slotted unit, said knives defining radial through-passages, interrupted by said connecting members between the knives, for the radially outward fiow of pulp from the interior of the roller, means for rotating the roller, a plurality of longitudinally extending, spaced, stationary defibrating and grinding knives mounted within the container and spaced from the walls thereof, said stationary knives being arranged close to each other and having end and intermediate connecting members between the knives to form a stationary, rigid, hollow slotted body said slotted body defining with said container wall an annular outlet space about said hollow slotted body, said roller being arranged within the slotted body thus provided, the edges of the stationary knives facing the roller and being in cooperative relation with the knives forming the working face of the roller, said stationary knives defining radial throughpassages, interrupted by said connecting members between the stationary knives, for the flow of pulp into said annular outlet space, a stationary inlet conduit passing through an end wall of said container and terminating within the openended roller and positioned for gravity feed of pulp to the interior of the roller whereby, upon rotation of the roller, pulp supplied to the interior of the roller is moved by centrifugal force through said through-passages between the knives of the roller to the working face where it is treated and radially outwardly through the through-passages between the stationary knives into said annular outlet space, and an outlet opening in said container in communication with 5, said annular space for discharge of treated pulp from said annular space.

2. The defibrating and grinding apparatus defined in cliam 1, in which the slotted roller is supported for rotation within the stationary hollow slotted body on a rotatable shaft which extends axially through said container and to one end of which a motor is connected, on which shaft is fixed a sleeve member carrying a plurality of spaced arms the outer ends of which are secured to said end and intermediate connecting members for the knives of said roller, at least the outermost of said arms being inclined.

3. The defibrating and grinding apparatus defined in claim 1, in which said roller is open at both ends and in which two stationary inlet conduits for gravity feed of pulp into the interior of said roller are provided, one for each end of said roller, to insure an even and continuous feeding of pulp along the entire length of said roller.

CORNELIUS LAVISTE.

References Cited in the file of this patent UNITED STATES PATENTS Number 20 Number Name Date Staub Nov. 4, 1837 Jordan et al Dec. 4, 1860 Jordan Feb. 5, 1861 Ponsar Jan. 5, 1909 Nicol Feb. 12, 1924 Clement May 26, 1931 Doyle Apr. 25, 1933 Wiener Dec. 19, 1933 Doyle Mar. 6, 1934 Trimbey July 14, 1936 Stevenson Jan. 18, 1938 Morden July 16, 1940 Lowe Mar. 14, 1944 Cawood et a1. Feb. 15, 1949 FOREIGN PATENTS Country Date Great Britain 1903 Germany Sept. 27, 1930 

